Generally, in a stationary fuel cell system, a reformer converts reforming fuel into hydrogen, and the hydrogen and oxygen in the atmosphere are supplied to a fuel cell and are reacted to generate electric power, which is supplied to private load devices being electric appliances such as light, TV, washer, air conditioner, refrigerator and the like. However, in the event of a power failure wherein the power supply from a system power source is cut off, the stationary fuel cell is also stopped. Therefore, a measure in the event of a power failure has to be taken into account.
Heretofore, in Patent Document 1 for example, there is described an electric power supply device for power failure which utilizes a battery of an electric vehicle in the event of a power failure to supply emergency electric power to electric appliances for household use. The electric power supply device for power failure described in Patent Document 1 is operated in such a way that upon detection of a power failure, the direct current power charged in the battery of the electric vehicle is supplied to a DC/AC converter, from which electric power is supplied to various electric appliances inside the house through a circuit breaker.
The aforementioned Patent Document 1 also describes, as another embodiment, one which is provided with solar cell panels and a storage battery besides the battery, wherein upon detection of a power failure, the electric power charged in the battery and the storage battery is supplied to various electric appliances, and the electric power from the solar cell panels is also supplied thereto in the case that the sunbeam in the daytime is sufficiently irradiated on the solar cell panels.
Further, in Patent Document 2, there is described an energy generating system, which is provided with a stationary power generating device for supplying electric power to private load devices of an independent house and an onboard power generating device mounted on an electric vehicle. In the system, when the electric power generated by the stationary power generating device is over the consumption by the private load devices, the surplus electric power is supplied to the battery of the electric vehicle, or when the electric power generated by the stationary power generating device is less than the consumption by the private load devices, the shortfall is replenished from the battery of the electric vehicle, so that the transfer of electric power can be done therebetween.
Patent Document 1: Japanese unexamined, published patent application No. 11-178241 (paragraphs 0022, 0049, 0050 and FIGS. 1 and 5)
Patent Document 2: Japanese unexamined, published patent application No. 2004-48895 (paragraphs 0019, 0035 and FIG. 1)